Instant p-doping and pore elimination of the spiro-OMeTAD hole-transport layer in perovskite solar cells.

An instant p-doping strategy employing 4--butyl-2-chloropyridine and -butyl peroxybenzoate for the spiro-OMeTAD hole-transport layer (HTL) in perovskite solar cells (PSCs) is proposed to replace the conventional 4--butylpyridine-doped HTL. The novel doping process eliminates the formation of pores in the HTL. Meanwhile, a 21.4% efficiency is achieved on the corresponding absolute methylammonium-free PSCs with significantly improved thermal and moisture stability.